[llvm] r241784 - [LAA] Rename IsRTNeeded to IsRTCheckAnalysisNeeded

[Adam Nemet]

Author: anemet
Date: Thu Jul  9 01:47:18 2015
New Revision: 241784

URL: http://llvm.org/viewvc/llvm-project?rev=241784&view=rev
Log:
[LAA] Rename IsRTNeeded to IsRTCheckAnalysisNeeded

The original name was too close to NeedRTCheck which is what the actual
memcheck analysis returns.  This flag, as the new name suggests, is only
used to whether to initiate that analysis.

Also a comment is added to answer one question I had about this code for
a long time.  Namely, how does this flag differ from
isDependencyCheckNeeded since they are seemingly set at the same time.

Modified:
    llvm/trunk/lib/Analysis/LoopAccessAnalysis.cpp

Modified: llvm/trunk/lib/Analysis/LoopAccessAnalysis.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/LoopAccessAnalysis.cpp?rev=241784&r1=241783&r2=241784&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/LoopAccessAnalysis.cpp (original)
+++ llvm/trunk/lib/Analysis/LoopAccessAnalysis.cpp Thu Jul  9 01:47:18 2015
@@ -373,7 +373,8 @@ public:
 
   AccessAnalysis(const DataLayout &Dl, AliasAnalysis *AA, LoopInfo *LI,
                  MemoryDepChecker::DepCandidates &DA)
-      : DL(Dl), AST(*AA), LI(LI), DepCands(DA), IsRTCheckNeeded(false) {}
+      : DL(Dl), AST(*AA), LI(LI), DepCands(DA),
+        IsRTCheckAnalysisNeeded(false) {}
 
   /// \brief Register a load  and whether it is only read from.
   void addLoad(MemoryLocation &Loc, bool IsReadOnly) {
@@ -405,8 +406,11 @@ public:
     processMemAccesses();
   }
 
-  bool isRTCheckNeeded() { return IsRTCheckNeeded; }
-
+  /// \brief Initial processing of memory accesses determined that we need to
+  /// perform dependency checking.
+  ///
+  /// Note that this can later be cleared if we retry memcheck analysis without
+  /// dependency checking (i.e. ShouldRetryWithRuntimeCheck).
   bool isDependencyCheckNeeded() { return !CheckDeps.empty(); }
 
   /// We decided that no dependence analysis would be used.  Reset the state.
@@ -446,7 +450,14 @@ private:
   /// dependence check.
   MemoryDepChecker::DepCandidates &DepCands;
 
-  bool IsRTCheckNeeded;
+  /// \brief Initial processing of memory accesses determined that we may need
+  /// to add memchecks.  Perform the analysis to determine the necessary checks.
+  ///
+  /// Note that, this is different from isDependencyCheckNeeded.  When we retry
+  /// memcheck analysis without dependency checking
+  /// (i.e. ShouldRetryWithRuntimeCheck), isDependencyCheckNeeded is cleared
+  /// while this remains set if we have potentially dependent accesses.
+  bool IsRTCheckAnalysisNeeded;
 };
 
 } // end anonymous namespace
@@ -471,7 +482,7 @@ bool AccessAnalysis::canCheckPtrAtRT(
   bool CanDoRT = true;
 
   NeedRTCheck = false;
-  if (!IsRTCheckNeeded) return true;
+  if (!IsRTCheckAnalysisNeeded) return true;
 
   bool IsDepCheckNeeded = isDependencyCheckNeeded();
 
@@ -653,7 +664,7 @@ void AccessAnalysis::processMemAccesses(
           // catch "a[i] = a[i] + " without having to do a dependence check).
           if ((IsWrite || IsReadOnlyPtr) && SetHasWrite) {
             CheckDeps.insert(Access);
-            IsRTCheckNeeded = true;
+            IsRTCheckAnalysisNeeded = true;
           }
 
           if (IsWrite)